The invention relates in general to a method and apparatus for tracking motion within a sequence of images. More specifically, the invention relates to a method and apparatus for efficient determination and computing of perspective transformation motion tracking parameters in a sequence of images.
A common requirement in the field of motion picture special effects is the need to track the motion of objects within a motion picture image sequence. The tracked motion of an object can be utilized, for example, to form composite image scenes in which the tracked objects are combined with other scene elements to move along with the tracked object. Alternatively, the tracking information related to a moving object can be utilized to remove unwanted motion effects from the image sequence, thereby stabilizing the image sequence to improve viewing characteristics. Still further, the tracking information may be utilized to track objects from scene to scene in a motion picture image sequence in order to apply special effects to the tracked object.
A variety of methods and devices have been proposed to detect and track movement in a sequence of images. The conventional methods and devices, however, are generally not efficient in computational requirements and speed, particularly when applied to determining and computing perspective transformation motion tracking parameters.
In view of the above, it is an object of the invention to provide a method and apparatus for efficient computing of perspective transformation motion tracking parameters in a motion image sequence.
The invention provides a method and apparatus for efficient computing of perspective transformation motion tracking parameters in a sequence of images. More specifically, a set of initial positions for N points defined as (xi yi) for i=1 to N corresponding to at least one input image in a sequence of images are defined. The initial positions are preferably chosen based on image features having good edge and corner definitions. A set of mapping parameters are then generated using a matrix processor to solve linearized equations that define a set of final positions. The mapping parameters are then applied to the initial coordinate positions to determine corresponding final positions.
These and other aspects, objects, features and advantages of the present invention will be more clearly understood and appreciated from a review of the following detailed description of the preferred embodiments of the invention, the accompanying drawings, and the appended claims.